Lieutenant-Governor John Graves Simcoe planned Yonge Street, which was built between 1793 and 1796 by the Queen's Rangers. By 1801, Timothy Rogers, a Loyalist from Vermont, had travelled the road and found an area on its western boundary immediately southwest of Newmarket very appealing. He applied for and received a grant for land totalling 40 farms, each of 200 acres (0.8 km2), and subsequently returned to Vermont to recruit families to operate those farms. By February 1802, he had set out for King Township with the first group of settlers for those forty farms. A second group followed later that month.

The area would become known as Armitage, in honour of its first settler Amos Armitage.[7] It was the first of King's settlements, and now part of Newmarket. Soon after the establishment of Armitage, the communities of Kettleby and Lloydtown were established to the west. More settlers arrived from New York, Pennsylvania, and other Loyalist enclaves over the subsequent years to populate the region, drawn by the abundant, fertile land being apportioned relatively cheaply to newcomers.

By 1842, the township consisted of 53,240 acres (215 km2) of land, of which 13,818 acres (56 km2) had been cleared and was being cultivated.[8] The principal villages at the time were Lloydtown, Brownsville (now Schomberg), Bogarttown (now a part of Newmarket), and Tyrwhitt's Mills (now Kettleby).[8]

In 1851, the township annexed from West Gwillimbury the portion of land north of its extant and east of the Holland River as a result of the formation of Simcoe County. Approximately 86,840 acres (351 km2) of land were administered by the township in 1878, according to the Historical Atlas of York County, but by 1973 this had been reduced to 82,000; some of its land has been ceded to what are now known as Newmarket, Aurora and Oak Ridges.

The first survey of King Township was conducted in 1800 by Hessian soldier Johann Stegmann.[5] At the time, the area's population was twenty residents. According to a letter by Benjamin Cody to the Newmarket Era published on 7 May 1892, there were church records listing births in the area, and the first white child in King may have been Sarah Rogers, born April 1800.[9] At least four children were born in King by July 1802.[9] By 1809, the township's population had increased sevenfold, to 160.[10] By 1842, the population of 2,625 residents was principally Irish, and also included those of English, Scottish, Canadian, and American descent.[8]

There is some evidence of a large Huron encampment at Hackett Lake. Residents in the area in the 1950s and 1960s discovered arrowheads and other archaeological items indicating a Huron presence. This is consistent with the fact that the Toronto Carrying-Place Trail, a major route used in the 17th and 18th centuries, passes through the township. The route was used by explorer Étienne Brûlé, who first travelled along the trail with twelve Huron guides in 1615.

Early settlements in the area developed primarily around gristmills and sawmills. These were important economic engines in the region during the 19th century, which resulted in the establishment of other communities and businesses nearby. By 1842, there were eight grist mills and 12 saw mills in King.[11] Some settlements have since been abandoned, or are no longer communities per se, including Bell's Lake, Davis Corners, and King Ridge.

A map of the southern portion of King Township from 1878. At the time, the township's boundaries extended to Yonge Street. The area between Bathurst Street and Yonge Street, shown as lots 61-95 on the map, have since been ceded to Richmond Hill, Aurora, and Newmarket.

The six wards of King. The varying shades of each colour represent the polling areas for that ward.

King Township was incorporated in 1850 as The Corporation of the Township of King. Its current mayor is Steve Pelligrini, who was sworn into office in December 2010. The Town Council includes the mayor and six councillors representing the township's six wards. The mayor is also a member of York Regional Council via double direct election.

In the 2014 municipal election, the mayorship was uncontested and Steve Pellegrini was acclaimed for a second term. Cleve Mortelliti was acclaimed for Ward 1 owing to no opposing candidates.[13] Candidates for the other wards were:[13]

The township draws revenues from various sources. The most significant in 2007 were municipal taxes (67.9% of revenue), fees and service charges (14.0%), water charges (4.3%), grants (3.5%) and reserves (2.9%). The most significant expenditures for 2007 are general municipal government (27.6%), recreation and culture (21.7%), transportation (17.8%), protection (16.6%) and environmental projects (11.6%).[14]

The Township offices reside at the King City Plaza, though a more appropriate permanent location is being investigated. In 2013, the township purchased the disused former Holy Name Catholic Elementary School building and adjacent land from the York Catholic District School Board for $2.95 million.[15]

The provincial riding of Oak Ridges—Markham is currently represented by Helena Jaczek, a member of the Ontario Liberal Party.[17] It was created as part of Ontario's re-districting to match provincial electoral districts with their federal equivalents. King was part of the Vaughan—King—Aurora electoral district from 1999 to 2007, York—MacKenzie from 1995 to 1999, and York North from Confederation to 1995. The portion of King north of Highway 9 is part of the York—Simcoe electoral district, represented by Julia Munro of the Progressive Conservative Party of Ontario.

Originally settled by United Empire Loyalists in the late 18th century, King is now influenced by the significant immigration and diversification resultant from its proximity to Toronto.

King Township's population grew by 2.1% between 2006 and 2011, most new residents settling in the communities of King City, Nobleton or Schomberg. The population density is 59.7 people per square kilometre; however, the Township is characterized by areas of extremely low density farming communities and the much higher density of its three major villages. In 2008, of the 19,640 residents in the township, 4,770 resided in King City, 3,100 in Nobleton, 1,970 in Schomberg, and 9,800 in other communities or rural areas.[18]

As of 2006, the median age of residents is 39.4; 30% of the population over 15 years of age is still single. Foreign-born residents accounted for 20% of the population. Only 3% of residents identify themselves as visible minorities.[19]

Of residents 15 years of age or older, 28% have a university certificate, diploma or degree. Another 18% have a college certificate or diploma, and 10% have a trade certificate or diploma. However, there is variability between age groups, as younger people are increasingly participating in higher levels of education.

Nearly 15% of all employed residents work from home. Almost 3% walk or bike to work sites within the community; 5% use public transit, and 75% drive or are passengers in private vehicles, to reach work destinations within the Greater Toronto Area.

The participation rate in the work force is 72.4%, with a 3.6% unemployment rate. The largest industries are:[20]

Construction and Manufacturing: 24%

Business services: 23%

Wholesale and Retail Trade: 17%

Health and Education: 12%

Finance and Real Estate: 8%

The median income for two-parent families is $90,364. For single-parent families, the median income is $43,673. The average value of a dwelling in King in 2006 was $386,416.

The Township of King is located between Toronto and Barrie, stretching from Bathurst Street to just east of Highway 50. King is accessible by Highways 400, 27, 9 and 11.

Public transportation is provided by York Region Transit (bus service) and GO Transit (bus and train services), but their services are limited in the township due to low population density. King City GO Station is the only train station in the township. York Region Transit's services are confined to the southeastern area, and GO bus serves the Nobleton and King City communities.

King's earliest settlement, Armitage, is now part of Newmarket. Its establishment was followed by those of Lloydtown and Kettleby. Subsequent settlements were founded near rivers, which provided the energy necessary to operate various mills. The earliest were based in Laskay, Kinghorn, and Eversley. The hamlet of Springhill was established later and flourished; it was renamed King City, now the largest community in the township.

Eversley is a hamlet that, although it has its own historical development, has slowly been subsumed into King City. It lies on King City's north-eastern edge, south of Snowball. It was also known as Tinline's Corners in the 1800s.

Glenville is a hamlet located in northeastern King, just south of the community of Ansnorveldt.

Heritage Park is a community of King City. It is a natural and wildlife park characterized by ravines and creeks, some of which feed the East Humber River. Portions of the park are in the King City Trail.

Kinghorn is a community of King City, located at the Jane Street-King Road intersection. It is a sparse residential area adjacent to Highway 400, and is home to the King Township Museum and The Kingbridge Centre.

Laskay is a hamlet located just west of King City and south of the King Road—Weston Road intersection.

Snowball is a growing hamlet located just north of Eversley, west of Aurora.

In the township, there are eleven sites designated Heritage Sites, including:

King Station was built in 1852 along the Northern Railway to serve Springhill (now King City). It was moved in 1989 to the grounds of the King Township Museum. It is believed to be the oldest surviving railway station in Canada, and was designated a heritage site in 1990.

King Emmanuel Baptist Church, formerly the King Christian Church until 1931, it was moved to the grounds of the King Township Museum in 1982, and designated a heritage site in 1992.

King City Cemetery, established in 1886, was designated a heritage site in July 2007.[21]

King City Cemetery Dead House built circa 1887 was designated a heritage site in 2001. It is an octagonal structure that was used to preserve the dead during the winter, during which grave-digging was not feasible. Octagonal dead houses were unique to the area bordering Yonge Street north of Toronto during the late 19th and early 20th century.

Eversley Presbyterian Church, a stone structure built in 1848, demonstrates the Scottish influence common in the area's early development. It was designated in 1984.

Glenville Methodist Church, a small frame structure built in 1859, which remained operational until 1952. It was designated in 1983 as a township heritage site.

King Christian Church Cemetery was the first burial grounds for Kettleby, built in 1850. It was designated a heritage site in 1986.

Laskay Temperance Hall, built in 1859 by the Sons of Temperance. It had been operated by the Laskay Women's Institute since 1910, and is now operated by the municipality. It was designated a Heritage Site in 1986.

The township's municipal tax revenue is divided into three streams. One portion is combined with that from other municipalities for education purposes, a second portion is used to finance regional projects managed by York Region, and the last portion is used for local services.

The most significant cultural service provided via municipal funding is the King Township Public Library, which operates four branches in the township.

Waste management is provided through the region, and is co-ordinated with programs offered in other towns in York Region. Weekly green bin compost collection began in September 2007 to complement the weekly Blue Box collection of recyclable material; collection of all other waste was reduced to once every two weeks.[22] Water and wastewater management is operated by the township, though these services are not available ubiquitously; some areas rely on well water and septic tanks.